Electric heaters of this kind are well known, having a base layer of insulation material in a support, such as of metal. At least one elongate electric heating element, such as of bare wire or ribbon form, is supported on the base layer.
When the heating element is provided of spiral form, extending from a periphery of the heater to a termination point within the heater, it is necessary to provide an electrically conducting link, such as of wire, strip or tape form, extending from the termination point to the periphery of the heater, for electrically connecting the heating element to a power supply.
A similar form of connecting link may also be required with any form of heating element which may have a termination within the heater or a tapping point intermediate the ends of the element and where it is necessary to provide an electrical connecting link between the termination or tapping point and the periphery of the heater.
It is known to provide a connecting link for this purpose in or under the insulation base of a heater. Such a link may be U-shaped, having an elongate portion with upstanding opposite end leg portions which are required to protrude from the surface of the insulation for connection purposes. Such a connecting link is known from European Patent Publication No. 0 630 169.
When the insulation base comprises compacted particulate material, such as microporous insulation material, it would be convenient and advantageous to embed such a link in the insulation base simultaneously with compacting particulate, that is powdered, insulation material into a dish-like support to form the base. A problem with this is that a link of wire, strip or tape form is not rigid and when held by the end leg portions and pressed into the insulation, during compaction thereof, it tends to bend in its elongate portion.